Sikaflex?

[Sans Bateau]

What is the recommended product to bed in new skin fittings, that is bronze ones for sea cocks, and plastic Airmar transducer?

Would I use the same product to seal a small gap at the tail of the keel/hull joint. It needs raking out thoroughly, there is rust starting to be visible in that area.

 

[prv]

291 is the (sticky) sealant, 292 is the full-on glue.

I used 291 to rebed all my skin fittings, with no trouble so far.

Pete

 

[30boat]

Nasa recommends silicone sealant for their plastic skin fittings because,according to them,sikaflex afects plastic.I followed their advice and have had no leaks in ten years.

 

[VicS]

The Sikaflex Users Guide
or the Sikaflex Marine Handbook
might be useful

 

[Tranona]

I would use a Polysulphide for both jobs. Think Boatlife Lifecaulk is back on the market but Arbo also do one.

 

[V1701]

What about CT1? Have used it to bed cheek blocks and backing plates, e.g. above the water line but pretty sure that would be suitable...

 

[alteredoutlook]

I used ct1 for smoothing hull/keel join

 

[Neil_Y]

Arbo are the best and also cheaper than Sika, then comes 3M 5200 in my view.
http://www.arbo.co.uk/index.asp?id=3

The current grade which is an improvement over the 1240 is arbo meric MP20


In Devon they had the same distributor for arbo products as sika, so I get the impression the distributor pushed sika harder at the marine market as it was far more expensive and hence would probably have given them bigger margins.
At one time you could get arbothane 1240 in the chandlers at Mountbatten, a top end adhesive sealant for a fraction of the cost of Sika.

 

[doug748]

As 30 boat.
I use Silicone, from down the pound shop, for all seacocks. Not perhaps for the hull/keel joint though.

 

[Sans Bateau]

I stopped off at Force 4 when I was out today, a tube of Sikaflex is £9.95, that snot exactly going to break the bank, so is there any reason to not use Sikaflex?

 

[doug748]

Some Sikaflex stuff is tricky to get apart, some very difficult. I have had good results keeping part used tubes in the deep freeze but sods law says, every time you need another squirt, it costs another ten quid.
Better, in my view, to use an inexpensive product you can use, and use up, around the house.
I have just taken out a seacock I put in with silicone four years ago. No stress at all and the seal was just as good as the day it was set, it would be cos it is excellent stuff. I think bedding underwater fittings, of the standard type, is a very simple application.

In fact I can't think of much on the boat I would use Sikaflex for, tho I mended my deck shoes with it once (didn't look good) and it made a good job of sticking a kitchen cupboard door to a freezer front to make it look "fitted" :-]

 

[Bobobolinsky]

I use Soudal Fix All £5 a tube

 

[Salty John]

For through hulls you need a polyurethane sealant such as 3M 5200 or Sikaflex 291.
Be aware that these are extremely strong adhesives and should not be used where parts have to be routinely separated. They are used by boat builders for through hulls and hull to deck joints.
Boat Life Life Seal is a compromise giving much better adhesion than silicone but not as uncompromising a grip as 5200.
Personally, I've always used 5200 for underwater through hulls and repairs.

 

[VicS]

What ever happened to Sealastik. The stuff we used to use before all these silicones, and polywhatstheirnames etc came along.

I have skin fittings put in with it 34 years ago .... still watertight!

 

[chewi]

I stopped off at Force 4 when I was out today, a tube of Sikaflex is £9.95, that snot exactly going to break the bank, so is there any reason to not use Sikaflex?

Apparently so.

as 30boat says, and I read it elsewhere too, Nasa say that oil based sealants can embrittle the plastic skin fittings, so they recommend silicon. I know of 2 boats in my limited sphere that have had nasa fittings shear off at the waterline, mine was mid-solent the other was ashore. Neither had been fitted by the current owners.

 

[forelle541]

For the best bond use Sikaflex 11FC Bonds well and is very flexible.

 

[rotrax]

What ever happened to Sealastik. The stuff we used to use before all these silicones, and polywhatstheirnames etc came along.

I have skin fittings put in with it 34 years ago .... still watertight!

I've got a tube of black sealastik-top stuff! Its a bit messy to clean up where it squidges out,thats all.

 

[VicS]

I've got a tube of black sealastik-top stuff! Its a bit messy to clean up where it squidges out,thats all.

The stuff I am thinking of was off white like putty in a tube. Linseed oil based.

The black stuff I can remember was was Bostik outdoor sealant and Bostik outdoor adhesive. Both equally messy.

 

[Lady Campanula]

I mended my deck shoes with it once (didn't look good) :-]

I had the rubber sole of my leather footwear glued back on by the Sikaflex demonstrator - remember the 'build a boat from a plywood sheet' competitions? - at a SIBS more than 10 years ago.

I'm still using them, still stuck securely, two Gulf wars, two old boats, and several grandchildren later. Real VFM....

 

[Kwik Decision]

Another vote for silicon sealent. Top tip is to apply sealent, assemble skin fitting in the boat, but don't do it up very tightly, or you will squeeze all the sealent out. The following day, once it has set, tighten it up to compress the sealent and get a good seal.

I've fitted my NASA log transducer fitting twice, using silicone as recommened. The first time it leaked, not much, but enough to require bucket and sponge treatment once a week. The second time I used the method above and it has been water tight for two seasons. I have also successfully fitted a new blakes seacock using this method.